Photocatalysis by utilization of inexhaustive solar energy is a promising green technology that effectively degrades persistent environmental pollutants. However, current photocatalysts suffer from limited visible light adsorption, low reactivity, instability, and high cost. Recently, graphitic carbon nitride (g-C3N4) has emerged as a novel polymeric photocatalyst and attracts a great attention because it is capable of adsorbing visible light, because it is reactive for contaminant removal (e.g., NO, pathogens), because it is physically and chemically stable in oxidative reactions, and because it is made from inexpensive organic precursors. We synthesized g-C3N4 samples from four different precursors (urea, melamine, dicyandiamide, and thiourea), and applied them for phenol degradation under visible light irradiation (&gt; 400 nm). The preliminary results show that g-C3N4 synthesized from urea has the highest phenol removal efficiency, with a 1st order rate constant of 0.026 min-1. The reaction rate constant is 6-8.7 folds higher than those from the other precursors. The results indicate that the g-C3N4 has a promising future in removal of waterborne contaminants, and that performance is likely affected by physical and chemical properties of g-C3N4. To enhance the photocatalytic performance, we will increase the surface area of g-C3N4 by etching templates and creation of a porous structure, extend the absorption spectrum of g-C3N4 by carbon doping, and improve charge separation by loading metals or forming heterojunctions with other photocatalysts (e.g., TiO2, BiVO4). We will next apply the optimized g-C3N4 for persistent waterborne contaminant removal (e.g., carbamazepine, atrazine) in a complex water matrix to address challenges for contaminant removal in real water. This study explores the potential application of a new visible-light-responsive photocatalyst for water decontamination, and sheds light on achieving sustainable water treatment and water reuse.

Visible-light-responsive graphitic carbon nitride for photocatalytic degradation of persistent waterborne contaminants

249th National Meeting (2015)

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